I don't have a problem with making it a state crime to be in the country illegally.

I don't have a problem with police checking identification of someone suspected of committing a crime.

I DO have a problem requiring everyone to always carry documentation on them, and giving law enforcement carte blanche to demand it for almost no reason.

This is a free country, not communist Russia. It is not required that residents of the US carry ID or documentation, unless you are operating a motor vehicle or buying a controlled substance. It should not be allowed for any law enforcement to demand ID unless you are suspected of committing another crime. Even in that case, you are innocent until proven guilty. The burden of proof should be on the accuser (the police), not on the accused. Nobody should have to prove that they are NOT illegal. That is flat out un-Constitutional (check the 4th, 5th, and 6th ammendments). It violates Unlawful Search and Seizure, it violates Innocent until proven Guilty, AND it violates the Right to Remain Silent.

Now if you get taken in for another crime like speeding or burglary and you cannot display ID, then I don't have a problem requiring you to come before a judge with proof of legal residency to avoid being charged with Illegal status.